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Marine viruses that infect marine microorganisms are recognized as major ecological and evolutionary driving forces, shaping community structure and nutrient and energy cycling in the marine environment. Nevertheless, the cellular mechanisms that govern these host-virus dynamics are largely underexplored. Recent reports highlighted a novel genomic inventory found in marine viruses which can encode auxiliary metabolic genes previously thought to be restricted to their host genomes. Thus, these genes can expand viral metabolic capabilities and energy transfer between host cells and their environment. A major challenge in our current understanding of host-virus interactions in the marine environment is to decode the wealth of genomic and metagenomic data and translate it into cellular mechanisms that mediate host susceptibility and resistance to viral infection. Emiliania huxleyi is a globally important coccolithophore forming massive algal blooms in the North Atlantic Ocean that are routinely infected and terminated by large DNA viruses, coccolithoviruses (EhVs). We explore the molecular and metabolic basis for these host-virus dynamics and the signal transduction pathways that mediate host-virus interactions. By combining genome-enabled technologies and analytical chemistry approaches, we were able to identify several fundamental metabolic pathways that mediate these host-virus interactions. We revealed the role of viral-encoded sphingolipid, redox and DMS metabolism and their function in determining host cell fate (e.g. PCD and autophagy) and viral replication strategies. We currently examine the transcriptomic remodeling of host-virus interactions at a single cell resolution in order to provide novel insights into the cellular mechanisms that govern the “arms race” of the virocell during algal blooms dynamics in the ocean. [mehr]

Crop plants represent the primary source of amino acids (AAs) for humans and livestock. Metabolite profiling and correlation-based network analysis (CNA) of seeds of a tomato Introgression Line mapping population revealed a clique of proteinogenic amino acids (Gly, Leu, Pro, Ser, Thr, and Val) concertedly changing at the metabolite level and sharing a set of closely related metabolic genes. QTL analysis revealed co-localization of the six amino acids on chromosome 2, 4 and 10. In silico analysis was used to quantify the effect of the clique on seminal structural network properties, highlighting its centrality in the network. Sequence analysis identified a unique set of 10 genes on chromosome 2 only, which were associated with amino acid metabolism and specifically the metabolism of Ser-Gly and their conversion into branched chain amino acids. Metabolite profiling of a set of sublines, with introgressions in chromosome 2, identified a significant change in the abundance of the six amino acids in comparison to M82. Expression analysis of candidate genes affecting Ser metabolism matched the observation from the metabolite data, suggesting a tightly coordinated regulation of the level of these amino acids. [mehr]

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